A NEEPCO spokesperson on Wednesday said the penstock (pipe) carrying water from the tunnel to the power house burst around 4.30 a.m. on October 7 and damaged the isolating valve, meant to stop the water flow, causing the tragedy.
NEEPCO General Manager Debotosh Bhatacharjee said they had been able to lower the intake gate to substantial level. "The water at the project site is receding. Once the water level falls, we will start rescue operations," he said.
However, the locals said the NEEPCO had failed to lower the intake gate and the water was not receding.
"There was no proper maintenance and the intake gate became non-functional. Its more than 48 hours after the gushing water entered the project site. But they are yet to lower the water level," said brother of Robert Baite, one of the three employees missing since Monday.
Apart from Baite, Prem Pal Balmiki, Joy Sing Timung and one contractor were working at the power house when the tragedy struck. The four are missing since then.
"The gate at the intake is being lowered by the NEEPCO emergency team. The dam level is also being lowered to mitigate the problem," she said adding experts from the NHPC and Bhakra have been rushed to the spot.
"It's an unavoidable accident. The reasons are being investigated," she said.
The Congress in Assam, however, blamed the tragedy on the central government for not releasing Rs 200 crore approved by the then Congress-led UPA government in 2014 for maintenance of the project.
"Major repairing of the project was due in 2014. The pipeline expired its life span in 2014. But it couldn't be done as the NDA government didn't release the amount approved by the UPA government," said Durga Das Boro, senior spokesman of the Assam Congress unit.
( With inputs from IANS )